Epidemiology of urinary infections in renal transplant recipients

Urinary tract infection (UTI) remains a significant cause of infectious complications in renal transplant recipients. We evaluated prospectively all the UTIs in 161 kidney recipients transplanted between July 2003 and July 2005. All patients received prophylaxis with sulfadoxine-pyrimethamine. We excluded asymptomatic bacteriuria. Forty-one patients (25%) suffered at least one UTI episode. Ninety-two episodes of infection were confirmed with an incidence rate of 97 UTI episodes per 100 patient-years. The most common clinical features were uncomplicated acute bacterial cystitis, 71 episodes (77%), and acute pyelonephritis, 21 episodes (23%). Microbiological isolation was confirmed in 58 episodes (63%). Bacterial infections were the most frequent etiologies: gram-negative bacilli in 52 (90%), gram-positive cocci in 4 (7%), fungal in 2 (3%), and one viral BK virus (2%) infection. The causative microorganisms were E. coli as the principal isolated agent in 41 cases (71%), including 10 (24%) that were extended-spectrum betalactamases (ESBLEC). All episodes showed a favorable course. The survival rate of the graft at the end of the study period was 90.7%, and the survival rate of the transplant recipients was 97.5%. The incidence of UTI in transplant patients who received antibiotic prophylaxis was high. E. coli (ESBLEC) was the main agent isolated. Uncomplicated UTI, the most frequent post transplantation infection, showed a good prognosis.